Many military training facilities do not have sufficient real estate to accomodate the range of standard ammunition, yet they are required to provide army personnel with realistic training. Frequently, because of the range limitation training rounds are chosen which have a limited range. It is desirable to have the training ammunition ballistically match the standard ammunition to the maximum range of interest. It is also important to have the training round similar in appearance and relatively inexpensive to manufacture.
The problem with prior art training rounds was that they failed to ballistically match the service round, to provide realistic training, and were too expensive to manufacture. The desirable maximum range of a kinetic energy training round is 8,000 meters at 10 degrees quadrant elevation. The prior art training round used with a M724A1, a spin stabilized projectile which is fired from a 105 mm rifled barrel at a muzzle velocity of about 5050 ft/s. The maximum range at 10 degrees quadrant elevation is about 11,000 meters compared to the desired range of 8,000 meters. Because the M724A1 is a higher drag projectile than the standard fin stabilized projectile it has to be launched at a higher muzzle velocity so that the drag differential between the two projectiles could be compensated for. Consequently, the range of ballistic match was insufficient for realistic training.
Another type of prior art training projectile was the XM901, which is basically a flare stabilized projectile having holes along the flare section. The holes are designed to attain a choked flow phenomenon at a predetermined mach number and range. After choked flow is achieved, the drag of the projectile will increase and the range will be limited. The problem with this prior art design is that it is expensive to manufacture and not particularly efficient. The XM901 matches the service round to about 2,000 meters, but not the service round effective range of 3,000 meters.